The effects of plant growth promoting diazotrophic bacteria on plant performance and yield increase under nutrient limiting conditions have been discussed for many years (Jha et al., 2008, 2009). The interest in these bacteria intensified from the 1970s and 1980s with the discovery of endophytic diazotrophs in graminaceous plants such as sugarcane, maize, wheat and rice (Baldani et al., 1997; Dobbelaere et al., 2003). Okon and Labandera-Gonzalez (1994) reviewed the results of field experiments with Azospirillum inoculants in many countries over a period of twenty years. These results showed that the inoculants were capable of increasing yields of agriculturally important crops from 5% to 30%. A number of rhizosphere bacteria have been developed as biofertilizers and biofungicides to minimize excessive use of inorganic fertilizers and protect the environment and plant health (Kennedy et al., 2004; Ahmad et al., 2006). Microbial products have been developed for agricultural purposes and are commercially available worldwide (Shen, 1997). The first US product consisting of a PGPR strain Quantum (B. subtilis) is available commercially (Gardener and Fravel, 2002; Niranjan et al., 2003; Schisler et al., 2004). Gardener and Fravel, (2002) and Schisler et al. (2004) reviewed Bacillus-based products available in the USA (Table 2.2). Yield increasing bacteria, a commercial product of a multi-strain microbial agent made up of Bacillus brevi Gordon et al., B. cereus Frankland, B. coagulans Hammer, B.
firmus, B. lichenformis, B. sphericus and B. subtilis, has been used for crop production for more than a decade in China (Mei et al., 1990; Tang, 1994; Shen, 1997). Ten microbe-based biofertilizers available on the market in the Philippines which are used for the production of rice, maize and other crops have reduced the use of chemical fertilizer by 30% to 50% (Mansalud, 2008). In Indonesia there are 41 commercial biofertilizers in use (Husen, et al., 2007). There are many reports worldwide on continuous research on the effects of PGPR which include laboratory, greenhouse and field experiments (Okon and Labandera-Gonzalez, 1994). The role played by other bacteria and Cyanobacteria genera on plant growth and health is in continuous investigation. Laboratory and greenhouse experiments have been very successful whereas field results have been inconsistent (Dobbelaere et al., 2001)).The variability in the performance of these PGPR has been associated with various environmental factors that may affect their growth and effects on plants (Ahmad et al., 2008).
19
Plant growth promoting rhizobacteria are constantly being screened worldwide to identify strains that are rhizosphere-competent for commercialization both as biofertilizers and biopesticides.
Bacillus has been extensively investigated both for plant growth promotion and as a biological control agent over the years in many countries. Bacillus species have been tested and developed into commercial biofertilizers in a number of countries including China, India, Indonesia and USA (Cawoy et al., 2011). Its importance stems from the fact that it is the most abundant of the soil bacteria, is easy to isolate, rhizosphere competent, spore-bearing which makes it stress resistant thereby prolonging its shelf life and the spores are easy to produce in large quantities (de Freitas et al., 1997; Kim et al., 1997; Cavagalier et al., 2004). Microbial inoculants may be applied as seed treatments, foliar sprays or soil amendments (Creus et al., 1996; Islam and Bora, 1998; Singh et al., 1999; Niranjan et al., 2003). Soil amendment with microbial inoculants has been found to produce better results (Kennedy et al., 2004; Kidane, 2004; Niranjan et al., 2004).
20 References
Adesemoye, A.O., Torbert, H.A. and Kloepper, J.W. (2009). Plant growth-promoting rhizobacteria allow reduced application rates of chemical fertilizers. Microbiological Ecology 58, 921–929.
Ahmad, F., Ahmad, I., Aqil, F., Wani, A. A. and Sousche, S. Y. (2006). Plant growth promoting potential of free-living diazotrophs and other rhizobacteria isolated from Northern Indian Soil. Biotechnology Journal 1, 1112-1123.
Ahmad, F., Ahmad, I. and Khan, M.S. (2008). Screening of free-living rhizospheric bacteria for their multiple plant growth promoting activities. Microbiological Research 163, 173- 181.
Akbar, P., Ghalavand, A., Modares Sanavy, A.M., AghaAlikhani, M. and Shoghi Kalkhoran, S.
(2011). Comparison of different nutritional levels and the effect of plant growth promoting rhizobacteria (PGPR) on the grain yield and quality of sunflower. Australian Journal of Crop Science 5 (12), 1570-1576.
Alagawadi, A.R. (2006). Mechanisms of microbial mineral solubilization. In: Alagawadi A.R.,.
Krishnarag, P.U, Jagadeesh, K.S., Kulkarni, J.S. and Kannaiyan, S. (Editors). Microbial Biotechnology. Narosa Pasli House. New Delhi, India, pp 202-207.
Alagawadi, A.R. (2006). Mechanisms of microbial mineral solubilization. In: Microbial Biotechnology. Alagawadi A.R., Krishnarag, P.U., Jagadeesh, K.S., Kulkarni, J.S. and Kannaiyan, S. (Editors). Narosa Pasli House, New Delhi, India, pp 202-207.
Alexander, D.B. and Zuberer, D.A. (1991). Use of chrome azurol S reagents to evaluate siderophore-production by rhizosphere bacteria. Biology and Fertility of Soils 2, 39-45.
Antoun, H., Beauchamp, C.J., Goussard, N., Chabot, R. and Lalande, R. (1998). Potential of Rhizobium and Bradyrhizobium species as plant growth promoting rhizobacteria on non- legumes: effect on radishes (Raphanus sativus L.). Plant and Soil 204, 57–67.
Asaka, O. and Shoda, M. (1996). Biocontrol of Rhizoctonia solani damping-off of tomato with Bacillus subtilis RB14. Applied Environmental Microbiology 62, 4081-4085.
Bacon, C.W., Yates, I.E., Hinton, D.M. and Merdith, F. (2001). Biological control of Fusarium moniliforme in maize. Environmental Health Perspectives 109, 325-332.
Baker, C.J., Stavelly, J.R. and Mock, N. (1985). Biocontrol of bean rust by Bacillus subtilis under field conditions. Plant Disease 69, 770-772.
21
Baldani, J.I., Caruso L., Baldani V.L.D., Goi, S.R. and Dobereiner, J. (1997). Recent advances in biological nitrogen fixation with non-legume plants. Soil Biology and Biochemistry 29, 911-922.
Baldani, V.L.D., Baldani, J.I. and Döbereiner, J. (2001). Inoculation of rice plants with the endophytic diazatrophs Herbaspirillum seropedicae and Burkholderia spp. Biology and Fertility of Soils 30, 485–491.
Bashan, Y. and Levanony H., (1991). Alterations in membrane potential and in proton efflux in plant roots induced by Azospirillum brazilense. Plant and soil 137, 99-103.
Beneduzi, A., Perez, D., Vorgas, K.L., Bodanese-zanettini H.M. and Pasaglia L. M. P. (2008a).
Evaluation of genetic diversity and plant growth promoting activities of nitrogen fixing bacteria isolated from rice fields in south Brazil. Applied Soil Ecology 39, 311-320.
Beneduzi, A., Peres D., daCosta, P.B., Bonadese-zanettini, H.M. and Pasaglia, L.M.P. (2008b).
Genetic and Phenotypic diversity of plant growth promoting Bacilli isolated from wheat fields in Southern Brazil. Research Microbiology 159 244-250.
Bent, E., Breuil, C, Enebak, S., and Chanway, C.P. (2002). Surface colonization of lodgepole pine (Pinus contorta var lati folia [Dougl. Engelm]) roots by Pseudomonas fluorescens and Paenibacillus polymyxa under gnotobiotic conditions Plant and Soil 241, 187–196.
Berger, F., Hong, L., White, D., Frazer, R. and Leifert, C. (1996). Effect of pathogen inoculum antagonist density and plant species on biological control of Phytophthora and Pythium damping-off by Bacillus subtilis in high-humidity fogging glasshouse. Phytopathology 86:
428-433.
Bijay-Singh, Yadvinder-Singh. and Sekhon, G.S. (1995). Fertilizer-N use efficiency and nitrate pollution of groundwater in developing countries. Journal of Contaminant Hydrology 20, 167-184.
Bockman, O.C. (1997). Fertilizer and biological nitrogen fixation as a source of plant nutrients:
perspective for future agriculture. Plant and Soil 194, 11-14.
Boddey, R.M., Baldani, V.L.D., Baldani, J.I. and Dobereiner, J. (1986). Effect of inoculation of Azospirillum spp. on the nitrogen accumulation of field grown wheat. Plant and Soil 95, 109-121.
Boddey, R.M., Urquiaga, S, Reis V. and Dobereiner, J. (1991). Biological nitrogen fixation associated with sugarcane. Plant and Soil 137, 111-117.
22
Boddey, R.M., Polidoro, J.C., Resende, A.S., Alves, B.J.R. and Urquiaga, S. (2001). Use of the
15N natural abundance technique for the quantification of the contribution of N2 fixation to sugarcane and other grasses. Australian Journal. Of Plant Physiology 28, 889-895.
Borsht, Z., Kerby, N.W., Gantar, M. and Rowell, P. (1993). Effects of root-associated N2-fixing cyanobacteria on the growth and nitrogen content of wheat (Triticum vulgare L.) seedlings. Biology and Fertility of Soils 15, 68–72.
Briat, J.F. 1992. Iron assimilation and storage in prokaryotes. Journal of General Microbiology 138, 2475-2483.
Brick, J.M., Bostock, R.M., Silverstone, S.E. (1991). Rapid in situ assay for indoleacetic acid production by bacteria immobilized on nitrocellulose membrane. Applied Environmental Microbiology 57, 535-538.
Brock, T.D. and Madigan, M.T. (1991). Biology of microorganisms. 6th Edition. Prentice Hall, New York, USA, pp 874.
Brown, M.E. (1974). Seed and root bacterization. Annual Review of Phytopathology 6, 181-197.
Cakmakcı, R., Kantar, F. and Sahin, F. (2001). Effect of N2–fixing bacterial inoculations on yield of sugar beet and barley. Journal of Plant Nutrition and Soil Science 164, 527–531.
Cakmakci, R., Donmez, F., Aydin, A. and Sahin, F., 2006. Growth promotion of plants by plant growth-promoting rhizobacteria under greenhouse and two different field soil conditions.
Soil Biology and Biochemistry 38, 1482-1487.
Cavaglieri, L., Orlando, J. Rodriquez, M.I., Chutze, S. and Etcheverry, M. (2004). Biocontrol of Bacillus subtilis against Fusarium verticillioides in vitro and at the maize root level.
Research in Microbiology 156, 748-754.
Cawoy, H., Bettiol, W., Fickers, P. and Ongena, M. (2011). Bacillus-based biological control of plant diseases. In: Pesticides in the Modern World - Pesticides Use and Management.
Stoytcheva, M. (Editor.). ISBN: 978-953-307-459-7, InTech, DOI: 10.5772/17184.
http://www.intechopen.com/books/pesticides-in-the-modern-world-pesticides-use-and- management/Bacillus-based-biological-control-of-plant-diseases. PP. 274-302. Accessed 8th of October 2012.
23
Chabot, R., Antoun, H. and Cescas, M.P. (1996a). Growth promotion of maize and lettuce by phosphate-solubilizing Rhizobium leguminnoserum biovar. phaseoli. Plant and Soil 184, 311-321.
Chabot, R. Antoun, H., Kloepper, J.W. and Beauchamp, C.J. (1996b). Root colonization of maize and lettuce by bioluminescent Rhizobium leguminoserum biovar. phaseoli. Applied Environmental Microbiology 62, 2767-2772.
Chalk, P.M. (1991). The contribution of associative and asymbiotic nitrogen fixation to the nitrogen nutrition of non-legumes. Plant and Soil 132, 29-39.
Chandanie, W.A., Kubota, M. and Hyakumachi, M. (2006). Interaction between plant growth promoting fungi and arbascular Mycorhizal fungus Glomus mosseae and induction of systemic resistance to anthracnose disease in cucumber. Plant and Soil 286, 209-217.
Chet, I. and Inbar, J. (994). Biological control of fungal pathogens. Applied. Biochemistry and Biotechnology. 48, 37-43.
Cook, R.J. (1993). Making greater use of introduced microorganisms for biological control of plant pathogens. Annual Review of Phytopathology 31, 53-80.
Creus, C.M., Sueldo, R.J. and Barassi, C.A. (1996). Azospirillum inoculation in pregerminating wheat seeds. Canadian Journal of Microbiology 42, 83–86.
De Freitas, J.R., Banerjee, M.R. and Germida, J.J. (1997). Phosphate solubilizing rhizobacteria enhance the growth and yield but not uptake of canola (Brassica napus L.). Biology and Fertility of Soils 24: 358-364.
De Freitas, J.R. (2000). Yield and N assimilation of winter wheat (Triticum aestivum L., var Norstar) inoculated with rhizobacteria. Pedobiologia 44, 97–104.
Dobbelaere, S., Croonenborghs, A., Thys A., Vande Broek, A. and Vanderleyden, J. (1999).
Phytostimulatory effect of Azospirillum brasilense wild type and mutant strains altered in IAA production on wheat. Plant and Soil 212, 155–164.
Dobbelaere, S., Croonenborghs, A., Thys, A., Ptacek, D., Vanderleyden, J., Dutto, P., Labandera- Gonzalez, C., Caballero-Mellado, J., Aguirre, J.F., Kapulnik, Y., Brener, S., Burdman, S., Kadouri, D., Sarig, S. and Okon, Y. (2001). Responses of agronomically important crops to inoculation with Azospirillum. Australian Journal Plant Physiology 28, 871-887.
Dobbelaere, S., Vanderleyden, J. and Okon, Y. (2003). Plant growth-promoting effects of diazotrophs, in the rhizosphere. Critical Reviews in Plant Sciences 22, 107-149.
24
Dwivedi, D. and Johri, B.N. (2003). Antifungals from fluorescent pseudomonads: biosynthesis and regulation. Current Science 12, 1693–1703.
Duijff, B.J., de Kogel, W.J., Bakker, P.A.H.M. and Schippers, B. (1994). Influence of pseudobactin 358 on the iron nutrition of barley. Soil Biology and Biochemistry 26, 1681–
1688.
Egener, T., Hurek, T. and Reinhold-Hurek, B. (1999). Endophytic expression nif genes of Azoarcus sp. strain and Klebsiella and their effects on rice roots. Biology and Fertility of Soils 28, 377-381.
Foldes, T., Banhegyi, I., Herpai, Z. Varga L., and Szigeti, J. (2000). Isolation of Bacillus strains from the rhizosphere of cereals and in vitro screening for antagonism against phytopathogenic, food-borne pathogenic and spoilage microorganisms. Journal of Applied Microbiology 89, 840-846.
Fuentez-Ramirez, L.E., Jimenez-Salgado, T., Abarca-Ocampo, I.R. and Caballero-Mellado, J.
(1993). Colonization of sugarcane by Acetobacter diazotrophicus, an indoleacetic acid producing bacterium isolated from sugarcane cultivars of Mexico. Plant and Soil 154, 145-150.
Galloway, J.N., Schlesinger, W.H., Levy, H.I., Michaels A.F. and Schnoor, J.I. (1995). Nitrogen fixation anthropogenic enhancement-environmental response. In: Pedraza R.O. 2008.
Recent advances in nitrogen-fixing acetic acid bacteria. International Journal of Food Microbiology 125, 25-35.
Gardener, B. B. M. (2004) Ecology of Bacillus and Paenibacillus spp. Agricultural systems symposium. The nature of microbes: Bacillus spp. Phytopathology 94, 1252-1258.
Gehard, E.K., Huang, D.X., Glick, B.R. and Greenberg, B.M. (2009). Phytoremediation and rhizoremediation of organic soil contaminants: Potential and challenges. Plant Science 176, 20-30.
Glick, B.R. (1995). The enhancement of plant growth by free-living bacteria. Canadian Journal of Microbiology 41, 109-117.
Glick, B.R. and Bashan, Y. (1997). Genetic manipulation of plant growth-promoting rhizobacteria to enhance biocontrol of phytopathogens. Biotechnology Advances 5, 353- 378.
25
Gloud, W.D. (1990). Biological control of plant root disease by bacteria. In: Biotechnology of plant-microbe interaction Nakas, J.P. and Hagedon, C. (Editors). McGraw-Hill, New York, USA, pp 287-317.
Guetsky, R., Shtienberg, E., Elad, D., Fiscer, Y. and Dinoor, A. (2002). Improving biological control by combining biocontrol agents each with several mechanisms of disease suppression. Phytopathology 92, 976-985.
Hafeez, F.Y., Yasmin, S., Arian, D. Zafar, Y. and Malik, K.A. (2006). Plant growth-promoting bacteria as biofertilizer. Agronomy for Sustainable Development 26, 143-150.
Handlesman, J.O., Sandra, F., Master, H.E., Wunderlich, L. and Graig, R.G. (1990). Biological control of damping-off of Alfalfa seedlings with Bacillus cereus UW85. Applied and Environmental Microbiology 56, 713-718.
Harari, A. Kigel, J. and Okon, Y. (1988). Involvement of IAA in the interaction between Azospirillum brazilense and Panicum miliaceum roots. Plant and Soil 110, 275-282.
Hashem, M.A. (2001). Problems and prospects of cyanobacterial biofertilizer for rice cultivation.
Australian Journal of Plant Physiology 28, 881–888.
Hegazi, N.A., Faye, M., Amin, G. Hamza, M.A., Abbas, M. M. and Morib, M.Y. (1998).
Diazotrophs associated with non-legumes grown in sandy soil. In: Nitrogen Fixation with Non-Legumes. Malik, K.A., Mirza, M.S. and Ladha, J.K. (Editors). . Kulwer, Dordrecht, pp 209-222.
Holt, J.G., (1993). Bergy’s Manual of Systematic Bacteriology, 9th Edition. Williams and Wilkins. Baltimore, Maryland, USA, pp 787.
Holt, J.G., Krieg, N.R., Sneath P.H.A., Staley, J.T. and Williams S.T. (1994). In: Bergy’s Manual of Determinative Bacteriology, 9th Edition. Williams and Wilkins Pub., MD, USA, pp 787.
Hurek, T., Handley, L.L., Reinhold-Hurek, B. and Piche, Y. (2002). Azoarcus grass endophytes contribute fixed nitrogen to the plant in an unculturable state. Molecular Plant-Microbe Interaction 15, 233-242.
Husen, E., (2003). Screening of soil bacteria for plant growth promotion activities in vitro.
Indonesian Journal of Agricultural Science 4, 27-31.
26
Husen, E., Simanungkalit R.D.M. and Irawani, R.S. (2007). Characterization and quality assessment of Indonesian Commercial Biofertilizers. Indonesian Journal of Agicultural Science 8, 31-38.
Idris, H.A., Labuschague, N. and Korsten, L. (2007). Screening rhizobacteria for biological control of Fusarium root and crown rot of Sorghum in Ethiopia. Biological Control 40, 97-106.
Illmer, P. and Schinner F., (1992). Solubilization of inorganic phosphates by microorganisms isolated from forest soil. Soil Biology and Biochemistry 24, 389-395.
Illmer, P. and Schinner, F. (1995). Solubilization of inorganic calcium phosphate solubilization mechanisms. Soil Biology and Biochemistry 27, 257–263.
Illmer, P., Barbato, A. and F. Schinner, F.(1995). Solubilization of hardly soluble AlPO4 with P- solubilizing microorganisms. Soil Biology and Biochemistry 27, 260–70.
Iruthayathas, E.E., Gunasckaran, S. and Vlassak, K. (1983). Effect of combined inoculation of Azospirillum and Rhizobium on nodulation and N2-fixation of winged beans and soybean.
Science and Hortculturae 39, 610-615.
Islam, N. and Bora, L.C. (1998). Biological management of bacterial leaf blight of rice (Oryza sativa) with plant growth promoting rhizobacteria. Indian Journal of Agricultural Science 68, 798–800.
Isopi, R., Fabbri, P., Del-Gallo, M. and Puppi, G. (1995). Dual inoculation of Sorghum bicolor (L.) Moench ssp. bicolor with vascular arbascular mycorhizas and Acetobacter diazotrophicus. Symbiosis 18, 43-55.
Jacobsen, B.J., Zidack, N.K. and Larson, B. J. (2004). The role of Bacillus-based biological control agents in integrated pest management systems: Phytopathology 94, 1272-1275.
Jagadeesh, K. S. (2006). Biological control of plant diseases by Fluorescent Pseudomonad. In:
Microbial Biotechnology. Alagawadi, A.R. Krishnarag, P.U. Jagadeesh, K.S., Kulkarni, J.S. Kannaiyan, S. (Editors). Narosa Pasli House, New Delhi, India, pp 202-207.
James, E.K., Olivares, F.L., Baldani, J.I. and Dobereiner, J. (1997). Herbaspirillum, an endophytic diazotroph colonizing vascular tissue in leaves of Sorghum bicolor L.
Moench. Journal of Experimental Botany 48, 785-797.
James, E. K. (2000). Nitrogen fixation in endophytic and associative symbiosis. Field Crops Research 65, 197-209.
27
James, E.K., Gyaneshwar, P., Mathan, N., Barraquio, Q.L., Reddy, P.M., Iannetta, P.P.M., Olivares, F.L., Ladha, J.K. (2002). Infection and colonization of rice seedlings by the plant growth-promoting bacterium Herbaspirillum seropedicae Z67. Molecular Plant- Microbe. Interaction 15, 894–906.
Jha, P.N. and Kumar, A. (2008). Endophytic colonization of Typha australis by a plant growth- promoting bacterium Klebsiella oxytoca strain GR-3. Journal of Applied Microbiology 103, 1311-1320).
Jha, P.N. and Kumar, A. (2009). Characterization of Novel Plant Growth Promoting Endophytic Bacterium Achromobacter xylosoxidans from Wheat Plant. Microbial Ecology 58, 179–
188
Jones, D.L. (1998). Organic acids in the rhizosphere- a critical review. Plant and Soil 205, 25-44.
Joshi, P. and Bhatt, A.B. (2011). Diversity and function of plant growth promoting rhizobacteria associated with heat rhizosphere in North Himalayan region. International Journal of Environmental Sciences 16, 1135-1146.
Karl, D., Bergaman, B., Capone, D., Carpenter, E., Letelier, R., Lipschultz, F., Pearl, H., Sigman, D. and Stal, L. (2002). Dinitrogen fixation in the world’s oceans. Biogeochemistry 57, 47- 98.
Kennedy, I.R. and Tchan, I. (1992). Biological nitrogen fixation in non-leguminous field crops:
Recent advances. Plant and Soil 141, 93-118.
Kennedy, I.R., Choudhury, A.T.M.A. and Kecske, L.M. (2004). Non-symbiotic bacterial diazotrophs in crop-farming systems: can their potential for plant growth promotion be better exploited? Soil Biology and Biochemistry 36, 1229-1244.
Kidane, E.G. (2004). Biocontrol of Three Fusarial Diseases. MSc. thesis, University of KwaZulu- Natal, Pietermaritzburg, Republic of South Africa.
Kim, D.S., Coo, R.J. and Weller, D. M. (1997). Bacillus sp. L324-92 for biological control of three root diseases of wheat grown in reduced tillage. Phytopathology 87, 551-558.
Khan, M. R., Talukdar, N. C. and Thakuria, D. (2003): Detection of Azospirillum and PSB in rice rhizosphere soil by protein and antibiotic resistance profile and their effect on grain yield of rice. Indian Journal of Biotechnology 2, 246–250.
Kloepper, J.W., Lifshitz, R. and Zablotowicz, R.M. (1989). Free-living bacteria inocula for enhancing crop productivity. Trends in Biotechnology 7, 386-389.
28
Kloepper, J.W., Ryu, C.M. and Zhang, S. (2004). Induced systemic resistance and promotion of plant growth by Bacillus spp. Phytopathology 94, 1259-1266.
Kulkarni, S. (2006). Role of microbes in plant disease management. In: Microbial Biotechnology.
Alagawadi, A.R., Krishnarag, P.U., Jagadeesh, K.S., Kulkarni, J.S. and Kannaiyan, S.
(Editors). Narosa Pasli House. New Delhi, India, pp 198-201.
Kumar, V. and Narula, N. (1999). Solubilization of inorganic phosphates and growth emergence of wheat by Azotobacter chroococcum. Biology Fertility of Soil 28, 301-305.
Kumar, B.S. D., Bergsen, I. and Martensson, A.M. (2001). Potential for improving Pea production by co-inoculation with fluorescent Pseudomonas and Rhizobium. Plant and Soil 229, 25-34.
Kumar, K. (2006). Endophytic association of Azorhizobium caulinodans for nodulation and nitrogen fixation in cereal crops. In: Microbial Biotechnology. Alagawadi, A.R., Krishnarag, P.U., Jagadeesh, K.S., Kulkarni, J.S. and Kannaiyan, S. (Editors). Narosa Pasli House, New Delhi, India, pp 13-28.
Landa, B.B., Hervas, A., Bethiol, W. and Jimenez-Diaz, R.M. (1997). Antagonistic activity of bacteria from the chickpea rhizosphere against Fusarium oxysporium f. sp. ciceris.
Phytoparasitica 25, 305-318.
Larkin, R.P. and Fravel, R. (1998). Efficacy of various fungal and bacterial biocontrol organisms for control of Fusarium wilt of tomato. Plant Disease 82, 1022-1028.
Leifert, C., Li, H., Chidburee, S., Hampson, S., Workman, S., Sigee, D., Epton, H.A.S. and Harbour, A. (1995). Antibiotic production and biocontrol activity by Bacillus subtilis CL27 and Bacillus pumilus CL45. Journal of Applied Bacteriology 78, 97–108.
Loper, J.E. and Buyer, J.S. (1991) Siderophores in microbial interactions on plant surfaces.
Molecular Plant-Microbe Interaction 4, 5–13
Loper, J.E. and Henkels, M.D. (1997). Availability of iron to Pseudomonas fluorescens in rhizosphere and bulk soil evaluated with an ice nucleation reporter gene. Applied and Environmental Microbiology 63, 99-105.
Lucy, M., Reed, E. and Glick, B.R. (2004). Applications of free living plant growth-promoting rhizobacteria. Antonie van Leeuwenhoek 86, 1–25.
Lynch, P.J. (2007). Roots of the second green revolution. Australian Journal of Botany 55, 493- 512.
29
McSpadden Gardener, B.B. and Fravel DR, (2002). Biological control of plant pathogens:
Research, commercialization, and application in the USA. Online. Plant Health Progress.
doi:10.1094/PHP-2002-0510-01-RV. Accessed 20th May 2010
Mahaffee, W.F. and Backman, P.A. (1993). Effects of seed factors on spermosphere and rhizosphere colonization of cotton by B. subtilis GBO3. Phytopathology 83, 1120-1125.
Malik, K.A., Bilal, R., Mehnaz, Z.S., Rasul, G., Mirza, M.S. and Ali, S., (1997). Association of nitrogen-fixing plant growth-promoting rhizobacteria (PGPR) with Kallar grass and rice.
Plant and Soil 19, 37-44.
Malik, K.A, Mirza, M.S., Hassn, U., Mehnaz, S., Rasul, G., Haurat, J., Bally, R. and Normand, P., (2002). The role of plant-associated bacteria in rice-wheat cropping system. In:
Biofertilizers in Action. Kennedy I.R. Choudhury. A.T.M.A. (Editors). Rural Industries Research and Development Corporation, Canberra, pp 73-83.
Mansalud, R.G. (2008). Harnessing Microbial Resources for Sustainable Crop Production: The Philippines Experience. Journal of faculty of agriculture 44 (12), 29-33.
Mathre, D.E., Cook, R.J. and Callan, N.W. (1999). From discovery to use. Traveling the world of commercializing biocontrol agents for plant disease control. Plant Disease 83, 972-982.
Mei, R.H., Chen, B., Lu, S., Chen, Y.X. (1990). Field application of yield-increasing bacteria.
Chinese Journal of Microecology 3, 30-34.
Mittal, V., Singh, O., Nayar, H., Kaur, H. and Tewar, R. (2008). Stimulatory effects of phosphate-solubilizing fungal strains (Aspergillus awamori and Penicillium citrinum) on the yield of chick pea (Ciceri arietinum L. cv. GPF2). Soil Biology and Biochemistry 40 718-727.
Mrkovacki, N. and Milic, V. (2001). Use of Azotobacter chroococcum as potentially useful in agricultural application. Annals of Microbiology 51, 145–158.
Myoungsu, P., Chungwoo, K., Jinchul, Y., Hyongseok, L., Wansik, S., Seunghwan, K. and Tongmin, S. (2005). Isolation and characterization of diazotrophic growth promoting bacteria from rhizosphere of agricultural crops of Korea. Microbiological Research 160, 127-133.
Nasbey, D C., Pascual, J.A. and Lynch, J.M. (2000). Effects of biocontrol strains of Trichoderma on plant growth Pythium ultimum populations, soil microbial communities and soil enzyme activities. Journal of Applied Microbiology 88, 161-169.
30
Nguyen, T.H., Deaker, R., Kennedy, I.R., Roughley, R.J. (2003). The positive yield response of field-grown rice to inoculation with a multi-strain biofertilizer in the Hanoi area, Vietnam.
Symbiosis 35, 231–245.
Nicholson, W.L. (2002). Roles of Bacillus endospores in the environment. Cellular and Molecular and Life Sciences. 59, 410-416.
Niranjan, R.S. Deepak, S.A., Basavaraju, P., Shetty, H.S., Reddy, M.S., Kloepper, J.W. (2003).
Comparative performance of formulations of plant growth promoting rhizobacteria in growth promotion and suppression of downy mildew in pearl millet. Crop Protection 22, 579-588.
Niranjan, S.R., Shetty, N.P. and Shetty, S.H. (2004). Seed bio-priming with Pseudomonas fluorescens isolates enhances growth of pearl millet plants and induces resistance against downy mildew. Journal of Pest Management 50(1) 41-48.
Okon, Y. and Labandera-Gonzalez, C.A. (1994). Agronomic application of Azospirillum: An evaluation of 20 years worldwide field inoculation. Soil Biology and Biochemistry 26, 1591-1601.
Omar, M.N.A., Mahrous, N.M. and Hamouda, A.M. (1996). Evaluating the efficiency of inoculating some diazatrophs on yield and protein content of 3 wheat cultivars under graded levels of nitrogen fertilization. Annals of Agricultural Sciences 41, 579–590.
O'Sullivan, D.J. and O'Gara, F. (1992). Traits of fluorescent Pseudomonas spp. involved in suppression of plant root pathogens. Microbiological Reviews 56, 662-676.
Pal, S. S. (1998). Interactions of an acid tolerant strain of phosphate solubilizing bacteria with a few acid tolerant crops. Plant and Soil 198, 169–177.
Pal, K.K., Tilak, K.V.B.R., Saxena, A.K., Dey, R. and Singh, C.S. (2001). Suppression of maize root diseases caused by Macrophomina phaseolin, Fusarium monoliforme and Fusarium graminearum by plant growth promoting rhizobacteria. Microbiological Research 156, 209- 223.
Pandey, A., Sharma, E., and Palni, L.M.S. (1998). Influence of bacterial inoculation on maize in upland farming system of Sikkim Himalaya. Soil Biology and Biochemistry 30, 379-384.
Patten, C. L. and Glick, B.R. (1996). Bacterial biosynthesis of indole-3-acetic acid. Canadian Journal of Microbiology 42, 207-220.